DC TO DC efficiency

[thingstodo]

Originally Posted by IamIan

... and with that many inverters you could power a whole house from your battery pack in case of power outages... ~30kw of Inverter AC is well over 200 amps of house 120 level AC ...

The modified sine wave inverters don't have a way to synchronize with each other. There would be lots of runtime on a single inverter, which could run the furnace, the water pump, the fridge, the deep freeze and maybe a few lights.

Originally Posted by IamIan

Sorry ... I don't see this setup of batteries and components getting you ~15kwh to the wheels in ~40 minutes or less.

I think you are right. And as has been mentioned, a DC system would work well and could have the range that I need, but I won't be setting up a DC EV system. I'll work on the AC system with a bunch of old junk that costs me nothing, or almost nothing, and see what I can learn.

Originally Posted by IamIan

Or get some tested numbers on batteries that have more than ~180Ah @12V @ ~150 Pounds @the Discharge Rate you are aiming for ( not at some ~20 Hour Rate )

I don't want to marginalize the batteries. They appear to be the center of the system, and the rest of the system revolves around them. They weigh as much as the rest of the truck, you need to build big sturdy boxes for them and they have to be connected properly, charged, and maintained.

They are just not very interesting compared to tuning the VFD, measuring the torque produced, estimating acceleration, trading off the size of the motor versus weight versus temperature rise and reduced life of the electric motor, driving the instrument cluster, etc. A couple of people are using industrial motors and controllers, but there is not a lot of real-world data out there (that I can find, anyway).

I am not a die-hard EV fan. If I have to add a 10 - 20 HP Briggs and Stratton engine to make some electricity to extend the range of whatever I come up with - that's also an option. Less gas is not my issue. Less cost would be nice, but again is not the issue. Understanding what is going on and troubleshooting myself is my goal. I *HATE* paying mechanics to connect a computer to my car and say 'I need to replace the Oxygen sensor'. But you just did that a month ago. What's causing the problem? 'Uh - the computer says I need to replace the Oxygen sensor - that'll be $600'.

If I ever get off my butt and build something, I'll start a build thread and I'm sure there will be much further discussion, about many things.

[IamIan]

Originally Posted by thingstodo

I think you are right. And as has been mentioned, a DC system would work well and could have the range that I need, but I won't be setting up a DC EV system. I'll work on the AC system with a bunch of old junk that costs me nothing, or almost nothing, and see what I can learn.

I don't think it is a DC or AC thing.
I think the issues are still the same weather it was a DC system or an AC system.

• You have a target range.
• You have a target weight limit.
• There is a net total system efficiency from battery to wheel.

Originally Posted by thingstodo

I don't want to marginalize the batteries. They appear to be the center of the system, and the rest of the system revolves around them.

They are just not very interesting

The batteries store the energy for all the vehicle needs for power and range... they limit everything else... a 1,000 HP electric motor and controller only has 10HP if that is all the batteries will give... and range is a function of energy use rate and again limited by what the batteries give.

I completely understand they might not be as interesting to you ... I find them very interesting myself ... but to each their own.

Originally Posted by thingstodo

I am not a die-hard EV fan. If I have to add a 10 - 20 HP Briggs and Stratton engine to make some electricity to extend the range of whatever I come up with - that's also an option.

DIY HEVs like that have been made by the DIY BEV crowd years before the OEMs got into HEVs.

The short version is that the ICE generator isn't free ... not in $ , not in space, not in weight ... what you spend on it ( $ , or L , or kg ) you are not spending on batteries... so there will be some break even points along that line.

• Smallest ... Regular non-Plug in HEVs like the Prius.
• Medium ... PHEVs for increased net vehicle efficiency.
• Large ... PHEVs Primarily runs as BEV , only using ICE rarely to extend range.

The size and weight of even ~10kw continuous output generator eats more than some people expect... the ICE itself is not the source of the ICE benefits ... the ICE benefits mostly come from the massive energy density of the fuel they run on, not on the ICE itself that is needed to make use of that fuel's energy density.

Originally Posted by thingstodo

Less gas is not my issue. Less cost would be nice, but again is not the issue. Understanding what is going on and troubleshooting myself is my goal.

And a good goal it is.
And a benefit of BEVs is their comparative simplicity to ICEs.

Originally Posted by thingstodo

If I ever get off my butt and build something, I'll start a build thread and I'm sure there will be much further discussion, about many things.

I think you've already started ... the trick is not to get too impatient and expect it to be done fast or easy ... you've begun the work of ironing out what your finished goals are , for energy use ... power output , weight , cost , etc ... lots of progress.